Pistachio rootstock named clone &#39;UCB1-D90&#39;

ABSTRACT

Disclosed is a new and distinct variety of pistachio rootstock called ‘UCB1-D90’ characterized in that, when compared to the industry standard ‘UCB1-D1’ rootstock, it has greater growth and tolerance to the soil salts of calcium chloride, sodium sulfate, sodium carbonate and sodium bicarbonate; greater growth and tolerance to high levels of dissolved salts in irrigation water; earlier vegetative bud break; and greater graft compatibility with commercial pistachio clones.

Latin name: Pistacia atlantica×Pistacia integerrima.

Varietal denomination: ‘UCB1-D90’.

BACKGROUND OF THE NEW VARIETY

The present invention comprises a new and distinct cultivar of hybridpistachio (Pistacia atlantica×Pistacia integerrima) used as a rootstockknown by the varietal name, clone ‘UCB1-D90.’ The clone, ‘UCB1-D90,’ isan in vitro, single selection of the segregating controlled cross of (P.atlantica×P. integerrima) made at Foundation Plant Services, Universityof California, Davis. The purpose of the selection program was todevelop rootstocks with superior tolerance to soil salts. Seedlings weretested in salt trials in the laboratory and compared to the ‘UCB1-D1’rootstock. Those seedlings that exhibited high tolerance to various soilsalts were selected. The new variety exhibits high tolerance tonumerous, common salts found in the soil and irrigation water.

The following characteristics distinguish clone ‘UCB1-D90’ from theindustry standard, ‘UCB1-D1’ rootstock:

1. Greater growth and tolerance to the soil salts, calcium chloride,sodium sulfate, sodium carbonate and sodium bicarbonate.

2. Greater growth and tolerance to high levels of dissolved salts inirrigation water.

3. Earlier vegetative bud break.

4. Greater graft compatibility with commercial pistachio clones.

ORIGIN AND ASEXUAL REPRODUCTION OF THE NEW VARIETY

Asexual reproduction of the new and distinct variety of rootstock wasaccomplished by germinating seed in vitro under aseptic conditions andpropagating the resulting seedlings using micropropagation techniques.Shoot epicotyl and hypocotyl tissue was collected from germinatingseedlings and placed on a standard growth media to produce shoots. Theshoots were sub-cultured and multiplied until desired numbers wereobtained and then transferred to standard rooting media for rooting.Rooted plantlets were then transferred to a peat:perlite media inacclimation chambers under 100% humidity. Field environmental parameterswere gradually introduced to harden plantlets which were thensuccessively transferred to larger pots in the greenhouse as their sizeincreased. These potted trees were used to establish field performancetrials. Subsequent evaluations have shown those asexual reproductionsare true-to-type to the original rootstock selection. Allcharacteristics of the original tree were established and appear to betransmitted completely through succeeding asexual propagations.

SUMMARY OF THE NEW VARIETY

The clone ‘UCB1-D90’ rootstock is characterized by its tolerance to highlevels of the soil salts, calcium chloride, sodium sulfate, sodiumcarbonate and sodium bicarbonate. In each case clone ‘UCB1-D90’ hadgreater growth in laboratory salt trials than the industry standardrootstock, ‘UCB1-D1.’ In another laboratory salt trial, media wassupplemented with the total salt load detected in San Joaquin Valleyirrigation water and also supplemented with twice that load. In allcases, growth of clone ‘UCB1-D90’ outperformed that of ‘UCB1-D1’ in thepresence of these high salt levels. Vegetative bud break of ‘UCB1-D90’was observed to be approximately 8 days earlier than ‘UCB1-D1’ and‘UCB1-D90’ graft compatibility with 5 commercial pistachio clones,‘Golden Hills,’ ‘Kerman,’ ‘Lost Hills,’ ‘Peters,’ and ‘Randy’ was 10%greater than the graft success rate of ‘UCB1-D1.’

DESCRIPTION OF THE ILLUSTRATIONS

The accompanying photographic illustrations show typical specimens ofvegetative growth of the new variety, with the color being as nearlytrue as is possible with color illustrations of this type:

FIG. 1 shows a 4 year old pistachio tree of the new variety.

FIG. 2 shows a close-up of the mature leaves of the new variety.

DESCRIPTION OF THE NEW VARIETY

The following detailed description sets forth the characteristics of thenew variety. The data which defines these characteristics was collectedunder natural daylight on plants grown in the central valley ofCalifornia in Stanislaus County in the greenhouse and in the field.Descriptions may vary in slight detail due to climatic, soil andcultural conditions under which the variety may be grown. Colordesignations are presented with reference to the Inter-Society ColorCouncil, National Bureau of Standards, except where common color namesare also included.

-   Tree: Trunk circumference 1 foot off the ground is 28.4 cm. Trunk    lenticels are approximately 2.4 mm in length and 1.1 mm in width.    Trunk lenticels are elliptic in shape. Trunk lenticel color is    strong brown [55. s.B]. Trunk lenticels number approximately 60 per    square inch. Bark color is dark grayish yellow [91. d.g.Y]. Branch    lenticels are approximately 2.2 mm in length and 0.6 mm in width.    Branch lenticels are linear in shape. Branch lenticel color is    strong brown [55. s.B]. Branch lenticels number approximately 62 per    square inch.-   Vegetative buds:    -   -   Size.—Approximately 50 mm in length and 4 mm in width.        -   Shape.—Conical.        -   Color.—Brilliant, yellowish green [130. b.y.G] with strong,            orange yellow [68. s.OY] exterior basal scales. As tips            unfurl they become strong purplish red [255. s.p.R]. First            vegetative buds of ‘UCB1-D90’ opened approximately 8 days            earlier than ‘UCB1-D1.’Leaflet blade color on the top and            bottom surfaces is vivid red [11. v.R]. At the junction of            the base of the petiole with the rachis, tissue color is            brilliant, yellowish green [130. b.y.G]. Expanding rachis            color is brilliant, yellowish green [130. b.y.G] at the            extreme tip and very dark purplish red [260. v.d.p.R] on all            sides elsewhere. Leaf venation pattern is pinnate and            alternate. Midrib and veins are brilliant, yellowish green            [130. b.y.G].-   Foliage: Leaves are pinnately compound composed of alternate    leaflets numbering between 14 and 17. Compound leaf size variations    are great but average approximately 46 cm in length and 47 cm in    width at the widest point. Young leaflets are glossy and dark    greyish red [20. d.g.R] on upper surfaces and moderate olive green    [125. m.OG] on lower surfaces. Older leaflet surfaces are strong    olive green [123. s.OG] on upper surfaces and moderate olive green    [125. m.OG] on lower surfaces. Leaflet shape is lanceolate with an    acute apex and cuneate base. There is great variation in leaf and    leaflet size depending on the time of the season, position on the    tree and tree age. Leaflet size varies considerably but averages 78    mm in length and 27 mm in width. Leaf venation pattern is pinnate    and venation is brilliant yellowish green [130. b.y.G]. The midrib    is prominent and the same color as the venation pattern. Leaf    margins are entire and surfaces are glabrous. Petiole and rachis    younger tissue upper and lower surface color is predominately strong    purplish red [255. s.p.R] with some strong yellowish green [131.    s.y.G] streaking on lower surfaces of older tissues. Petiole length    varies considerably but averages 60 mm in length from point of    rachis attachment to basal leaflet, and is glabrous with no wings.    Rachis length varies considerably and averages about 35 cm in    length.-   Salt tolerance: Different concentrations of individual salts that    contribute to soil salinity and alkalinity ranging from 0 to 10,000    mg/l were added to the culture medium that rootstock was growing in.    Each clone-salt combination was replicated four times. Observations    were taken on visual injury symptoms and growth measured by number    of shoots and leaves per plant. Clone ‘UCB1-D90’ rootstock is    characterized by its tolerance to high levels of the soil salts,    calcium chloride (at 10,000 mg/l), sodium sulfate (at 10,000 mg/l),    sodium carbonate (at 1,000 mg/l) and sodium bicarbonate (at 1,000    mg/l). As measured on a growth scale of 1 to 10, in the case of each    of these salt trials clone ‘UCB1-90D’ had greater growth than the    industry standard rootstock, ‘UCB1-D1.’ In another salt trial, media    was supplemented with the comparable total salt load detected in San    Joaquin Valley irrigation water (Sanden, B. et al. 2009. Large-Scale    Utilization of Saline Groundwater for Irrigation of Pistachios    Interplanted with Cotton. 2009 Progress Rpt. of CA Pistachio Comm.)    plus twice the detected salt load. In all cases, growth of clone    ‘UCB1-D90’ outperformed that of ‘UCB1-D1’ in the presence of high    soluble salts.

Having thus described and illustrated the new variety of rootstock, whatis claimed as new and desired to be secured by plant letters patent is:1. A new and distinct variety of pistachio rootstock substantially asillustrated and described called ‘UCB1-D90’ characterized in that, whencompared to the industry standard ‘UCB1-D1’ rootstock, it has greatergrowth and tolerance to the soil salts of calcium chloride, sodiumsulfate, sodium carbonate and sodium bicarbonate; greater growth andtolerance to high levels of dissolved salts in irrigation water; earliervegetative bud break; and greater graft compatibility with commercialpistachio clones.